Grinding wheel truing mechanism



W- B. SEIDEL GRINDING WHEEL TRUING MECHANISM Jan. 29, 1963 4Sheets-Sheet 1 Filed Nov. 8, 1960 INVENTOR. WILLIAM B. SEIDEL fjvbwav"ATTORNEYS Jan. 29, 1963 w. B. SElDEL GRINDING WHEEL TRUING MECHANISM 4Sheets-Sheet 2 Filed NOV. 8, 1960 W. B- SEIDEL GRINDING WHEEL TRUINGMECHANISM Jan. 29, 1963 4 Sheets- Shegt :5

Filed NOV. 8, 1960 sol.

Jan. 29, 1963 w. a. SEIDEL GRINDING WHEEL TRUING MECHANISM Filed Nov. 8.1960 4 Sheets-Sheet 4 A1], ISOL.

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| ICR 3,075,513 GRINDING WHEEL TRUllNG MEQHANISM Wiiiiam B. Seidel,Cincinnati, Ohio, assiguor to The Qincinnati Miliing Machine Co.,Cincinnafi, Ohio, a corporation of Shin Filed Nov. 8, 19:30, Ser. No.68,070 Claims- (Cl. 125-11) This invention relates to a grinding wheeltruing mechanism adapted for use in a precision grinding machine.

in the manufacture of angular contact annular ball bearings, it isnecessary to grind a workpiece profile which includes both an arcuateportion and an adjacent straight portion. it is a common practice not tomake the straight portion exactly tangent to the arcuate portion, butrather to leave a slight corner condition between the two surfaces whichwill hold the balls in the arcuate ball track. The arcuate portion mustbe ground to a depth slightly greater than that to which the straightprofile portion is ground. Each of the two surfaces is generally groundin a separate operation, the arcuate track being ground first and thestraight portion being ground in a subsequent operation. It is a betterpractice to grind both the arcuate ball track and the fiat land in oneoperation.

In grinding both profile surfaces in one operation, an

ccurate grinding wheel profile must be generated and maintained. Thisrequires an accurate truing mechanism which will create a peripheralcontour, the parts of which will not change relative to one another insucceeding truing operations. With a wheel profile having a slightcorner between straight and arcuate portions thereof, cam guidance atthe corner is diificult. Moreover, the use of a cam restricts theflexibility of use of the machine since a different cam is required foreach contour.

It is therefore an object of this invention to provide a truingmechanism whereby an arcuate portion and adjacent straight portion maybe trued on a grinding wheel periphery by a single truing tool in asingle truing operation without cam guidance.

It is a further object to provide a mechanism whereby an arcuate profileportion and an intersecting adjacent straight profile portion may betrued on the periphery of a grinding wheel.

It is another object of this invention to provide a truing mechanismwhereby the path of the truing tool may be altered to true a variety ofgrinding wheel profiles having straight and arcuate profile portions.

Still another object is to provide a mechanism for truing a straightprofile portion and an arcuate profile portion in one continuousmovement of the truing tool which is simply and inexpensivelyconstructed yet which is accurate through repeated operations.

Other objects and advantages of the present invention should be readilyapparent by reference to the following specification, considered inconjunction with the accompanying drawings forming a part thereof, andit is to be understood that any modifications may be made in the exactstructural details there shown and described, within the scope of theappended claims, without departing from or exceeding the spirit of theinvention.

A truing mechanism constructed in accordance with the preferred form ofthis invention utilizes a single point truing tool mounted in a truingslide member. The truing slide member is received for reciprocalmovement in a truing yoke which is pivotal relative to the grindingwheel. A rotary driving member develops a torque which is divided by themechanism to produce movement of the truing slide in the yoke andpivotal movement of the yoke, the yoke remaining stationary while theslide is moved therein. The relative movements of the slide and yoke areadjustable to produce movement of the truing tool through a path bywhich an arcuate profile portion inter- 3,fi75,5l3 Patented Jan. 29,M963 sected by a straight profile portion may be trued as well as aprofile in which the straight portion is tangent to the arcuate portion.The mechanism is accurate and the same profile may be repeatedly trued.

The construction and operation of the truing mechanism are described inthe following detailed description with reference to the attacheddrawings wherein;

FIG. 1 is an elevational view of the truing mechanism.

FIG. 2 is a sectional View of FIG. 1 on line 2-2.

FIG. 3 is a sectional view of FIG. 2 on line 3-3.

FIG. 4 is a sectional view showing the details of the drive inputmechanism.

FIG. 5 is a sectional View of FIG. 4 on line 5-5.

FIG. 6 is a schematically represented hydraulic circuit to operate thetruing attachment.

FIG. 7 is an electrical control circuit for operation of the hydrauliccircuit of FIG. 6.

FIG. 8 is a sectional view of FIG. 3 on line 88.

FIG. 9 is a partial section of a grinding wheel showing the profile ofthe grinding periphery.

As shown in FIG. 1, the truing mechanism is located behind the grindingwheel it which is rotatably supported in a grinding machine Wheelhead11. The truing mechanism is supported by a truing carriage 12 which isreceived by a slide housing 14 that is fixed in the wheelhead l1 andforms a part thereof. The grinding wheel 19 rotates about an axis whichis fixed relative to the slide housing 14 of the wheelhcad. The truingcarriage 12 is movable toward and away from the grinding wheel It byselected rotation of a compensation screw 16 which is axially fixedrelative to the slide housing 14 and threadedly engaged with the truingcarriage. The compensation screw 16 is utilized to move the truingcarriage 12 relative to the slide housing 14 toward the grinding wheel19 to maintian the truing mechanism in a position to perform a truingoperation as the grinding wheel it! is reduced in diameter through use.

Fixed on the end of the truing carriage l2 and forming a part thereof isa bracket is in which a yoke 2a is pivotally received. The yoke 20 isheld in the bracket 13 by pins 22, 24 fixed therein and extending fromthe yoke into the bracket where they are in pivotal contact with balls26, 28 respectively. The balls 26, 28 are held in place in the bracket18 by pin seats 3-9, 32 respectively, fixed in the bracket. Alsocontained in the bracket it; above the yoke 29 is a gear mechanism 34-by which a truing tool 42 is moved during a truing operation. Themechanism 34 is actuated by a pair of pistons $6, 38 (FIG. 6) which arereceived in a cylinder block it; that is fixed on the rear of thebracket 13.

The single point truing tool 42 is carried in the yoke 23 for truing thegrinding wheel it? when moved across the peripheral cutting surfacethereof. As shown in FIGS. 2 and 3, the truing tool 42 is received in atruing slide member 44 which is received in the yoke it) on antitrictionballs is. The anti-friction balls it are received in ball tracks 48, St}in the yoke 2t} and held in spaced relationship to one another by cagemembers 52, 54. The truing tool 42 is adjustable toward and away fromthe grinding wheel It} by rotation of a screw as which is receivedthrough a sleeve 53 that extends through a slot 659 at the rear of theyoke Ed. The truing tool 42 is held in a fixed angular position in thetruing slide 44 since it has a longitudinal slot 62 (see FIG. 8) on oneside engaged by a key pin 64 fixed in the truing slide. When the truingtool 42 is axially positioned to true a particular radius, with thepoint of truing tool 42 a predetermined distance from the axis definedby the center of pivot balls 26, 2d, a locking screw 66 is tighteneddown to rigidly fix the tool in the truing slide 44.

By moving the truing slide 44 in the yoke 2t? while holding the yokestationary, a straight profile portion may be sweets is trued on thegrinding wheel it). By stopping the movement of the truing slide 44 inthe yoke 29 and then by swinging the yoke, the point of the truing tool42 will move in an arcuate path for truing an arcuate profile portion onthe peripheral surface of the grinding wheel The gear mechanism 34 isshown in detail in PEG. 4. Limited rotary motion is introduced to theactuating mechanism 34 from the pair or" reciprocating pistons 36, 355in the cylinder block 4% (FIG. 6). Connected to each of the pistons as,33 is a drive chain 6%. The chain 68 is pinned at its center to to arotatable sleeve '72. "the sleeve 72 is received in annular bearings 74,6 which are received in a retainer member '77 fixed in the bracket 33.The sleeve is rotatable around the pin 22, ball 25, and pin seat so asthe chain ss is moved. On the lower end of the sleeve '72 is a gear 78Which is fixed for rotation tl1erewith by a key 8%. A nut 82 holds thegear 78 on the sleeve '72. In mesh with the gear 78 is a sector gearwhich is fixed to the upper end of a shaft 85 which extends into theyoke 29, as shown in FIG. 1, where it is journalcd for rotation. Asshown in FIG, 3, a pinion gear 88 is fixed on the lower end of the shaftas. The pinion 38 is engaged with a rack gt} which is machined on therear of the truing slide 44.

By the described mechanism, reciprocal motion of the pistons 36, 38(FIG. 6), to which the chain n3 is attached at each end, is convertedinto rotary motion at the sleeve '72 (HQ. 4). The rotary motion of thesleeve 72 produces a torque which is transmitted from the gear 78through the sector gear so to the shaft 86. The shaft 36, pinion $8, andrack 98* converts the torque into motion of the truing slide. To allowthe truing slide 44 to be moved by the pinion 88, the yoke 23 must offermore resistance to movement than the slide 5 or otherwise the yoke wouldtend to be swung by the movement of the gear 72. An annular drag seal 2is received in the bracket 18 and engaged with an annular surface 94 onthe top of the yoke The drag seal 92 in addition to keeping grindingdirt out of the gear mechanism, creates a resistance to movement of theyoke which, in combination with antifriction balls as, renders thetruing slide 44 more freely movable than the yoke. Consequently rotarymotion of the shaft 86 in the yoke 2i) will occur and the truing slide44 will move transversely in the yoke.

if the movement of the truing slide in the yoke 26 is stopped before therotary input of sleeve 72 is exhausted, the remaining torque produced atthe sector gear 84 may be utilized to swing the yoke in the bracket 18.Therefore a pair of stop members 98, 161) (FIG. 2) are received in oneside of the yoke 24} and a third stop member M2 (PEG. 8) is received inthe same side of the yoke but extends through the truing slide 44 to theopposite side where it is adapted to engage the bottom of a counterboredportion 194 thereof. (As shown in FIG. 2, stop 19?; extends from theside of the yoke Ztv and is covered by a guard member 96 which isnormally received over the adjusting knob 162a of the stop duringmachine operation.) The stop S (FIG. 2) is a fixed stop and limits theextreme movement of the slide 44 at the right side of the yoke 29. Thestop 1% is an adustable stop which may be used in place of the fixedstop 98 to restrict the extreme movement of the slide 44'; to the rightin the yoke 26) but to a selected point to the left of the fixed stop93. As shown in FIG. 2 the truing slide 44 is in its extreme rightposition. The left side stop 102 (FIG. 8) is adustable relative to theyoke 2b in which it is threadedly received. Assuming that the stop 16-2is at its extreme left adjustment, the dimension 1% represents theallowable movement of the truing slide 44 in the yoke or the length ofthe strai ht path which the truing tool 42 may trace. 7 7

By the construction described, assume that the sleeve 72 (FIG. 4) may berotated through a reciprocal rotary movement of 180 degrees by operationof the pistons 36, 33 (FIG. 6). Of this motion, 90 degrees in' onedirecltion is necessary to move the truing slide 44 (FIG. 2) fromengagement with the fixed stop 98 through a dis tance 1% to engagementwith the left stop 162. When the stop 102 is engaged by the truing slide44 and the sleeve 72 (FIG. 4) continues to rotate in the same direction,the balance of the rotary movement, degrees, is transferred to the yoke29 to swing it thrOugh an arcu ate path. The engagement of the stop Hi2by the truing slide 44 fixes the truing slide in the yoke 2 and theforce created by the continued rotary movement of the sleeve '72 in thesame direction is transmitted through the stop 182 to the yoke 2d. Theforce produced thereby tending to swing the yoke 2% is greater than theresistance to movement of the yoke created by the drag seal 92. The yoke2b then becomes more freely movable than the truing slide 44- duringcOntinued rotation of the sleeve 72 through the second 90 degrees.

By the combination of the movement of the truiug slide 44 in the yoke2t) and the subsequent pivotal movement of the yoke, the truing tool iscarried along a path havinga straight portion and an arcuate portion.The point of the vtruing tool 52 then may be utilized to true a grindingWheel l0 having a profile contour which includes a straight portion andan arcuate portion. If the stop 102 (FIG. 8) is positioned such that thepoint of the truing tool 42 is swung about a radius which is equal tothe perpendicular distance from the center of the radius to the straightportion of the path traced by the point, the straight portion of thepath would be tangent to the arcuate portion of the path. The mechanismmay thcnbe used to true such a profile on the periphery of the grindingwheel ill. The point of tangency and the center C of the arcuate portiondefine a centerline of pivot CL, FIG. 9, used as a reference line foraltering the relationship of the straight and arc-uate portions of thepath traced by the truing tool 42.

If the stop 192 (MG. 8) is adjusted to terminate th movement of thetruing slide 44 in the yoke 29 at a place where the point of the truingtool 42 (FIG. 3) is swung about a radius which is greater than theperpendicular distance from the center of the radius to the straight poition of the path, the straight portion of the path traced by the truingtool would intersect the arcuate portion of the path, that is, thestraight portion would not be tangent to the arcuate portion. One formof this condition is shown in FIG. 9. The grinding wheel 15} has astraight profile portion res and an arcuate profile portion 110. Theavailable straight movement of the truing tool is represented bydimension 112 and is equal to th dimension 106 in FIG. 8. If allavailable straight movement were used, the resulting form would be astraight portion tangent to an arcuate portion. The stop 102, however,is adjusted to the right (FIG. 8) to shorten the path of the truingslide by an amount equal to dimension 114 to offset the start of thearcuate path from the center line of pivot CL. When the straightmovement of the truing slide 42 is stopped, the swing of the yoke 26begins. The point of the truing tool 42 now traces an arcuate path theradius R of which is greater than the perpendicular distance 116 fromthe center C of the arcuate portion to the straight portion of the path.Thus a stepped relation is created on the grinding wheel periphery, thestep being represented by the dimension S, and the straight portion 108intersects the arouate portion 110. The offset dimension 114 may beexpressed relative to the radius R and step S by the formula;

' ofiset= /R (RS) Therefore, by calibrating the knob 162a (FIG. 8) onthe stop 102, the truing mechanism'may be conveniently adjusted to truea range of stepped forms on the grinding wheel.

In the specific embodiment described herein, the total straight movementis assumed to be suchthat at full 'rnoven'ient of the'truingslided i, astraight'suri'ace tangent to an arcuate surface is trued. By extendingthe beyond the dimension lilo (H6. 8), a straight surface which wouldintersect the arcuate surface but which would produce no step. In such acase the offset would be in the opposite direction from the centerlineof pivot CL from the ofiset 114 shown in FIG. 9.

In truing the wheel form in FIG. 9, the truing tool 42 would move fromposition 118 through a straight path and succeeding arcuate path andstop at position 129. The truing tool must then be returned to itsstarting position 118. This is done by reversing the action of thepistons 36, 38 (FIG. 6). The sleeve 72 (FIG. 4) is then rotated through180 degrees in the opposite direction. Initially, the truing slide 44moves more freely since the shaft 86 is rotated in a direction tendingto move the truing slide from engagement with stop 162 (FIG. 8) towardstop 93 (H6. 2) and the drag seal ;92 (FIG. 4) opposes movement of theyoke in the opposite direction. Therefore the truing slide 44 movesfirst in the yoke 29 and then the yoke finally swings to its startingposition. In such a motion, the truing tool 42 would be moved away fromthe grinding wheel ll} (FIG. 9) and returned to its starting positionfile without contacting the grinding wheel. Truing contact then occursonly when the truing tool 42 moves from the start position 118 to thestop position 12%.

To insure that the mechanism tunes the same contour each time and thatthe spaced relationship of the aircuate portion and the straight portionof the periphery remains constant, the return swing of the yoke 20 tothe starting position must end at the distance from the line CL eachtime. Therefore, a stop pin 122 (FIGS. 4, 5) is fixed in a cap 124 whichis adjustable relative to the top of the bracket 18 and may be lockedthereto by a draw-down bolt 126. The stop pin 122 extends through anarcuate clearance slot 128 in the bracket 18. The lower end of the stoppin 122 is adapted to engage a stop 130 fixed in an angle bracket 132which is secur d to the top of the yoke 29 and moves therewith. As shownin FIG. 5, the stop 13% is engaged with the stop pin 122 at the startingposition 118. In a truing operation, the yoke 29 would movecounterclockwise (as viewed in FIG. 5) and the stop 13o would move awayfrom the stop pin 122 during the truing of the arcuate portion of thegrinding wheel periphery. Upon the return swing of the yoke 20, the stop13a would move back toward the stop pin 122 for engagement therewith.The use of the rigid stop 122 to terminate the return swing of the yoke2% then places the yoke in the same starting position relative to lineCL each time. Rigid stops 98, 100, 1ii2 (FIGS. 2, 8) in the yoke 20control the movement of the truing slide 44 and the result is repeatedmovement of the truing tool through an identical ath.

P An electrical control circuit is shown in FIG. 7 for operation of thetruing hydraulic circuit shown in FIG. 6. In the starting condition, thepiston as is in its forward position as shown and piston 33 is in theretracted position. Therefore, limit switch lLS is operated and limitswitch 2L8 is in t o released condition at the start of a truing cycle.(The trip point of both limit switches lLS and 2L8 may be adjusted inmachine set up for a particular job.) With limit switch llLS operatedrelay SCR is energized. Switch SW1 is momentarily closed to start thetruing cycle. During the moment that switch SW1 is closed, relay lCR isenergized through that switch and immediately relay 2CR is energizedthrough contacts of relays 1CR and SCR. Relay 20R latches around thecontacts of relay SCR. Immediately, relay ECR is energized through thecontacts of relays lCR, 2CR and CR (normally closed). Solenoid ISOL isthen energized through contacts of relay 30R.

When soleonid 1501. is energized the plunger of the reversing valve 134shifts to the right from the position slide movement the mechanism wouldtrue shown in PEG. 6. The main fluid pressure line 136 is connected tothe fluid line 138 which is connected in the cylinder block as to theleft side of piston 36. Line 14a is connected through the valve 134 toreturn line 142. Piston 36 is forced to the right and the other piston38 moves to the left as the chain 68 is moved. The sleeve 72 is rotatedcounterclockwise, and the truing tool movement begins. At this timelimit switch 11.3 is released and relay 50R is deenergized. Switch SW1may now be released since the latch circuit through contacts of relayslCR and 56R (normally closed) will hold relay lCR energized.

After the pistons 35, 38 have completed their stroke, limit switch ZLSis operated by piston as have completed their stroke, limit switch 2L8is operated by piston 36 and as a result, relay 60R is energized. Whenrelay CR is energized relay 3C3 is dropped to deenergize solenoid lSOL.Relay 42CR is energized at this time through contacts of relays 5C3.(normally closed), lCR, and dCR. Relay 40R latches around contacts ofrelay 6C3. Solenoid 2501. is now energized through contacts of relay4-CR and the plunger of valve 134 shifts to the left. Pressure line 1136is connected to fluid line 140, and return line 142 is connected toiluid line 138. The movement of the pistons 36, 38 is reversed to returnthe truing tool' 4-2 to its starting position. Limit switch 21.8 isreleased immediately as the reverse movement begins, dropping relay GCR,and the limit switch 1L3 is operated when the return is completed. RelaySCR is energized when limit switch lLS is operated. Relays 1CR and 40Rare dropped when relay ECR is energized. When relay 10K is deenergized,relay 208. is also cleenergized, and when relay 4GB. i deenergized,solenoid ZSOL is deenergized.

The truing cycle is then completed, the truing tool having moved fromits starting position to its finished position and then returned to thestarting position. The length of the straight portion of the path of thetruing tool 42 relative to the arcuate portion is determined by thelength of movement of the slide 4 in the yoke 2d allowed by the settingof the stops 1%, N2 relative to one another and to the fined stop 93 andthe amount of rotary movement of thes leeve '72 produced by the pistons36, 38. The relationship of the straight portion to the arcuate portionis determined by the adjustment of the stop 1 92 relative to thecenterline of pivot CL (FIG. 9).

if the stops il -319, 1G2 (FIGS 2, 3) are adjusted to hold the truingslide 44 in a fixed position in the yoke, the entire rotary movement ofthe sleeve '72 (FIG. 4) would be transmitted to the yoke 29 which wouldrotate with the sleeve 72. The stop 122 (FIG. 5) would then be adjustedcounterclockwise to allow a predetermined amount of arcuate movement ofthe yoke beyond the point shown. The full 180 degrees of movement of thesleeve 72 can be transmitted to move the yoke through a 180 degree swingfor truing an arcuate profile across the entire grinding wheel width 1&9FIG. 9). The stop 122 would then be moved in the slot 128 to the endopposite that in which the stop is shown to allow for the full swing. Asshown, the stop 122 is in a position which would allow for a swing ofthe yoke 26 of approximately degrees with full movement of the truingslide 44 through the distance 1%. The range of swing in the mechanismdescribed can therefore be adjusted to any value between 90 and degrees.It a radius of less than 180 degrees is desired on the profile with nostraight portion, the stop 122 may be set in the appropriate position toprovide an accurate starting position. The trip plungers of limitswitches 1LS and 21.5 (FIG. 6) would have to be adjusted to operate thecontrol relays at the proper time since the pistons 36, 38 would notcomplete full travel in the cylinder block as.

lt is understood that the specific arcuate movements scream referred toherein are for purposes of illustration only and are not intended tolimit the scope of this invention.

What is claimed is:

1. In a grinding machine having a grinding Wheel with a contouredprofile thereon, a truing mechanism comprising in combination, apivotally movable member mounted adjacent the grinding wheel, a slidablymovable member received in said pivotally movable memher for transversemovement therein, a truing tool recoived in said slidably movable memberand extending therefrom toward said riiiding wheel, means initially torender one of said movable members more freely movable than the other ofsaid movable members, means to render the other of said movable membersmore freely movable than said one movable member after a predeterminedmovement of said one movable member, a drive member operativelyconnected to both of said movable members, one at a time in onedirection in accordance with relative freedom of movement therebe tweenfor truing a straight portion and an arcuate portion on the profile or"said grinding wheel, and means to reversely move said drive memberwhereby said movable members move in the reverse direction one at a timeto return said truing tool to a starting position.

2. in a grinding machine having a grinding wheel with a contouredprofile thereon, a truing mechanism comprising in combination, a bracketmounted adjacent the grinding wheel, a pivotally movable member mountedon said bracket, a slidably movable member received in said pivotalmember for transverse movement therein, means to render said slida'olemember more freely movable than said pivotal member, a truing toolreceived in said slidable member and extending therefrom toward saidgrinding wheel, a rotatable drive shaft journaled in the pivotal memberand connected to said slidable member for movement thereof when rotated,a drive member connected to said drive shaft, means to rotate said drivemember a predetermined amount initially to transmit rotation to saiddrive shaft in the pivotal member and move said slidable member therein,and means to stop movement of said slidable member in said pivotalmemher before said drive member has rotated said predetermined amountand to connect said drive shaft to said pivotal member for pivotalmovement thereof, said truing tool thereby moved for truing a straightportion and an arcuate portion on the profile of said grinding wheel.

3. In a grinding machine having a grinding wheel with a contouredprofile thereon, a truing mechanism comprising in combination, a bracketmounted adjacent the grinding wheel, a pivotally movable member mountedon said bracket, a slidably movable member received in said pivotalmember for transverse movement therein, a truing tool received in saidslidable member and extending therefrom toward said grinding wheel,means to render said slidable member more freely movable than saidpivotal member, a rotatable drive shaft journaled in the pivotal memberand connected to said slidable memher for movement thereof when rotated,a drive member journaled in the bracket and connected to said driveshaft, means to rotate said drive member a fixed amount in one directioninitially to transmit rotation to said drive shaft in the pivotal memberand move said slidable member therein, means to step movement of saidslidable member in one direction in said pivotal member before saiddrive member has rotated said fixed amount and to connect said driveshaft to said pivotal member for pivotal movement thereof in onedirection a predetermined amount, said truing tool thereby moved fortruing a straight portion and an arcuate portion on the profile of saidgrinding wheel, means to efiect rotation of said drive member said fixedamount in the other direction, and means to stop movement of saidslidable member in the other direction in said pivotal member beforesaid drive member has rotated said fixed amount and to connect saiddrive shaft to said pivotal member for pivotal movement thereof in theother direction a pred termined amount, said truing tool therebyreturned to a starting position.

4. In a grinding machine having a grinding wheel with a contouredprofile thereon, a truing mechanism comprising in combination, a bracketmounted adjacent the grinding wheel, a pivotally movable member receivedin said bracket on an axis, a slidably movable member received in saidpivotally movable member for transverse movement therein, a truing toolreceived in said slidably movable member and extending therefrom towardsaid grinding wheel, means to render said slidably movable member morefreely movable than said pivotally movable member, a rotatable driveshaft journaled in the pivotally movable member and spaced from saidaxis, said shaft connected to said slidably movable memher for movementthereof when rotated, a drive member journaled in said bracket forrotation on said axis and connected to said drive shaft for rotationthereof, means to rotate said drive member a fixed amount one way andthe other way, a pair of adjustable stop members received in saidpivotally movable member for engaging said slidably movable member tostop movement thereof before said drive member rotates said fixed amountand to connect said drive shaft to said pivotally movable member formovement thereof, the adjustment of said stop members determining therelative amount of movemerit of said movable members eifected by saidfixed rotation of the drive member and the direction of said fixedrotation determining the direction of movement of said movable members,and means to advance said pivotally movable member toward said grindingwheel 5. in a grinding machine having a grinding wheel with a grindingprofile including an arcuate portion and a straight portion, a truingmechanism comprising in combination, a truing carriage received adjacentsaid grinding wheel, a yoke pivotally received in said carriage, a pairof transversely spaced stops in said yoke, a truing slide received insaid yoke for movement between said stops, a truing tool fixed in saidtruing slide and extending therefrom toward said grinding wheel, a driveshaft journaled in said yoke and connected to said truing slide, saiddrive shaft operable, when a torque is applied thereto, to move saidtruing slide from one of said stops to the other of said stops andthereafter to pivot said yoke for movement of said truing tool to truesaid straight and arcuate portions, and means to apply a torque to saiddrive shaft.

6. In a grinding machine having a grinding Wheel with a grinding profileincluding an arcuate portion and a straight portion, a truing mechanismcomprising in combination, a truing carriage mounted adjacent saidgrinding wheel, a yoke pivotally received in said carriage on an aXis, apair of transversely spaced stops in said yoke, 21 truing slide receivedin said yoke for movement between said pair of stops, a truing toolfixed in said truing slide and extending therefrom toward said grindingwheel, a rotatable drive shaft journaled in said yoke and spaced fromthe pivot axis thereof, said drive shaft connected to said truing slidefor movement thereof from one stop to the other stop of said pair ofstops and thereafter for pivotal movement of said yoke when a torque isapplied to said drive shaft, and a drive mechanism operable to produce atorque and including a drive member journaled in said carriage androtatable about the pivot axis of said yoke, said mechanism connected tosaid drive shaft for transmission of said torque thereto to effectmovement of said truing slide and said yoke for truing said straight andarcuate profile portions.

7. in a grinding machine having a grinding wheel with a grinding profileincluding a straight portion and an arcuate portion, a truing mechanismcomprising in combination, a truing carriage received adjacent saidgrinding wheel, a yoke pivotally received in said carriage, a pair oftransversely spaced stops in said yoke, a truing slide received in saidyoke for movement between said steps, a truing tool fixed in said truingslide and extending therefrom toward the grinding wheel, a rack fixed tosaid truing slide, a rotatable drive shaft journaled in said yoke, saidshaft having a pinion fixed thereto and engaged with said rack, a dragmember received in said carriage and engaged with said yoke, said dragmember effective to impede movement of said yoke and to render saidtruing slide more freely movable than said yoke, means to apply a torqueto said shaft to effect movement of said truing slide from one of saidstops to the other of said stops and thereafter to pivot said yoke apredetermined amount in one direction, said truing tool thereby tracinga path for truing said straight portion and said arcuate portion, andmeans to reverse said torque to effect movement of said truing slidefrom the other of said stops to the one of said stops and thereafter topivot said yoke said predetermined amount in the other direction.

8. In a grinding machine having a wheelhead and a grinding wheelrotatably received therein, said grinding wheel having a grindingprofile including a straight portion and an arcuate portion, a truingmechanism comprising in combination, a truing carriage received in saidwheelhead, a pivotally movable yoke received in said carriage on anaxis, a positive stop in said carriage adapted to engage said yoke, apair of transversely spaced stops in said yoke, a truing slide receivedin said yoke for movement between said pair of stops, at truing toolfixed in said trning slide and extending therefrom toward said grindingwheel, a rack fixed to said truing slide, a rotatable drive shaftjournaled in said yoke, said drive shaft parallel to the pivotal axis ofsaid yoke and spaced therefrom, a pinion fixed to said drive shaft andengaged with said rack, a drag member received in said bracket andengaged with said yoke to render said truing slide more freely movablethan said yoke, means to apply a torque to said drive shaft to effectmovement of said truing slide from one stop to the other stop of saidpair of stops and thereafter to pivot said yoke a predetermined amountaway from said positive stop, said truing tool thereby tracing a pathfor truing said straight portion and said arcuate portion, means toreverse said torque applied to said drive shaft to effect movement ofsaid truing slide from the other stop to the one stop of said pair ofstops and thereafter to pivot said yoke to engage said positive stop,and means to adjust the other stop of said pair of stops relative to theone stop of said pair of stops to change the path traced by said truingtool for altering the relation of said straight portion to said arcuateportion.

9. In a grinding machine having a wheelhead and a grinding wheelrotatably received therein, said grinding wheel having a grindingprofile including a straight portion and an arcuate portion, a truingmechanism comprising in combination, a truing carriage received in saidwheelhead for movement toward said grinding wheel, said carriage havinga bracket extending therefrom, a pivotally movable yoke received in saidbracket on a pivot axis, an adjustable positive stop received in saidbracket and adapted to engage said yoke, a pair of adjustabletransversely spaced stops in said yoke, a truing slide received in saidyoke for movement between said pair of stops, a truing tool fixed insaid truing slide and extending therefrom toward said grinding wheel, arack fixed to said truing slide, a rotatable drive shaft journaled insaid yoke, said drive shaft spaced from and parallel to the pivot axisof said yoke, a pinion fixed to said drive shaft and engaged with saidrack, a drag member received in said bracket and engaged with said yoke,said drag member effective to render said truing slide more freelymovable than said yoke, means to apply a torque to said drive shaft inone direction to move said truing slide from one stop to the other stopof said pair of stops and thereafter to pivot said yoke away from saidpositive stop a predetermined amount for movement of said truing tool insaid straight and arcuate paths to true said straight and arcuateportions of said grinding wheel profile, the relative adjustment of saidpair of stops determining the relative length and relationship of saidstraight and arcuate paths and the positive stop determining thestarting position from which said truing tool is moved, means to reversesaid torque to rotate said drive shaft in the other direction and movesaid truing slide from the other stop to the one stop of said pair ofstops and thereafter to pivot said yoke to engage said positive stop,and means to advance said carriage toward said grinding wheel forpositioning said truing tool relative to the periphery of said grindingwheel.

10. In a grinding machine having a wheelhead and a grinding wheelrotatably received therein, said grinding wheel having a grindingprofile including a straight portion and an arcuate portion, a truingmechanism comprising in combination, a truing carriage received in saidwheelhead for movement toward said grinding wheel, said carriage havinga bracket extending therefrom, a pivotally movable yoke received in saidbracket on an axis, a positive stop received in said bracket and adaptedto engage said yoke, a pair of transversely spaced stops in said yoke, atruing slide received in said yoke for movement between said pair ofstops, a drag seal received in said bracket and engaged with said yoke,said seal effective to render said truing slide more freely movable thansaid yoke, a truing tool fixed in said truing slide and extendingtherefrom toward said grinding wheel, a rack fixed to said truing slide,a rotatable drive shaft journaled in said yoke and extending therefrom,said drive shaft parallel to and spaced from the pivot axis of saidyoke, a gear fixed to said drive shaft outside said yoke, a pinion fixedto said drive shaft in said yoke and engaged with said rack, a drivemember journaled in the bracket on the pivot axis of said yoke, saiddrive member having a drive gear fixed thereon and engaged with saidgear, means to apply a torque to said drive member in one direction toeffect movement of said truing slide from one stop to the other stop ofsaid pair of stops and thereafter to effect pivotal movement of saidyoke a predetermined distance away from said positive stop for truingsaid straight and arcuate portions of said grinding wheel profile, meansto reverse said torque to effect movement of said truing slide from theother stop to the one stop of said pair of stops and thereafter to pivotsaid yoke to engage said positive stop, means to adjust the other stoprelative to the one stop of said pair of stops for altering therelationship of said straight and arcuate paths, and means to advancesaid carriage toward said grinding wheel.

2,294,492 Wilson Sept. 1, 1942

5. IN A GRINDING MACHINE HAVING A GRINDING WHEEL WITH A GRINDING PROFILEINCLUDING AN ARCUATE PORTION AND A STRAIGHT PORTION, A TRUING MECHANISMCOMPRISING IN COMBINATION, A TRUING CARRIAGE RECEIVED ADJACENT SAIDGRINDING WHEEL, A YOKE PIVOTALLY RECEIVED IN SAID CARRIAGE, A PAIR OFTRANSVERSELY SPACED STOPS IN SAID YOKE, A TRUING SLIDE RECEIVED IN SAIDYOKE FOR MOVEMENT BETWEEN SAID STOPS, A TRUING TOOL FIXED IN SAID TRUINGSLIDE AND EXTENDING THEREFROM TOWARD SAID GRINDING WHEEL, A DRIVE SHAFTJOURNALED IN SAID YOKE AND CONNECTED TO SAID TRUING SLIDE, SAID DRIVESHAFT OPERABLE, WHEN A TORQUE IS APPLIED THERETO, TO MOVE SAID TRUINGSLIDE FROM ONE OF SAID STOPS TO THE OTHER OF SAID STOPS AND THEREAFTERTO PIVOT SAID YOKE FOR MOVEMENT OF SAID TRUING TOOL TO TRUE SAIDSTRAIGHT AND ARCUATE PORTIONS, AND MEANS TO APPLY A TORQUE TO SAID DRIVESHAFT.